That sphere was only 860 miles in diameter, fitting comfortably between Salt Lake City and Topeka, Kansas, on a map. It was striking, especially considering that the water available for humans use in our daily lives is only a very small fraction of that; the vast majority of the Earth’s water is saltwater, and most of the freshwater is tied up in glaciers.

How big would a sphere of just the freshwater available to humans be? Reader Jay Kimball of 8020Vision, his interest piqued, went ahead and made such a graphic:

When you’re trudging through the pouring rain to the office, it seems like the Earth possesses an infinite amount of water, a not-insignificant amount of which is dripping down your collar. But when you see an image like this one, produced by the USGS, it hammers home the reality of the situation: the water’s all spread out in a very thin layer, like a millimeter of frosting on a cake. If you gathered all the world’s water—from oceans, lakes, groundwater, water vapor, everything—into a sphere, it would have a diameter of 860 miles. That’s the distance between Salt Lake City and Topeka, Kansas.